Mold vs. mould?

Mold is the correct spelling for American English. If you live outside of the United States, the correct spelling is typically mould.

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What is the difference between mold and mould?

You know the dark, filmy material that grows in damp spaces? That, my friend, is called mold. But if you live in England or Australia, there’s a good chance it’s spelled mould instead. So, what’s the difference? 

There is none. Mold and mould are simply different spellings for the same word. “Mold” is more common for American English, while British English speakers prefer “mould.” 

What does mold mean?

The word mold (also spelled mould) is a noun and verb with three general associations: form, fungi, and soil. All verb forms associated with the infinitive ‘to mold’ include: 

  • Mold/molds or mould/moulds (present tense)
  • Molded/moulded (past participle)
  • Molding/moulding (present participle)

Mold = form

The noun mold often references a frame, template, structure, or prototype. For instance, a mold might be a hollow container that accepts liquid materials to form a solid when cooled (such as metal, plastics, baked goods, and gelatin)

Likewise, a mold can be a certain type of style, character, or manner. In this case, the noun is similar to words like disposition, nature, and temperament

Sentence examples:

  • “The liquid is then poured into a cast-iron mold, where it hardens into a bar in about 90 seconds.” — Bloomberg
  • “… before the gelatin starts to set, stir in the whipped cream in batches and pour into the mold of your choosing.” — Houston Chronicle
  • “Nathan fits the mold that BYU has recruited during Kalani Sitake’s tenure at BYU.” — Sports Illustrated

The verb mold references the act of using a mold (noun). For instance, we can physically mold a malleable substance into a particular shape or figuratively mold someone through influence. In any case, when something can be molded, the correct term to use is moldable (adjective). 

Sentence examples: 

  • “In aerospace, investment castings are used to mold alloys into engine components…” — The Science Times
  • “… the cloth is sent to the Fendi workshop in Florence, where it is hand-cut and molded into the house’s iconic rectangular shape.” — NYT Style Magazine
  • “The internet and the modern fame machine is molding a future generation of basketball stars…” — ESPN

Speaking of molds, there’s also the noun molding (not to be confused with the present participle of the verb mold). In this case, molding is an object created by molding (forming) something or, in some contexts, a decorative surface. 

Sentence example:

  • “On a hunch, I slipped a piece of molding into place to check how it looked over the high ridges of the tiles.” — The New York Times

Synonyms

(n.): Blueprint, brand, build, cast, container, die, form, frame, matrix, model, shape, type.

(v.): Construct, create, configure, design, fashion, forge, form, frame, make, shape, sculpt, throw.

Mold = fungi

The noun mold or mould also references the fuzzy fungal growth that occurs in warm, damp environments. 

Sentence examples:

  • “They were forced out of their four-bedroom house in Dallas because of toxic mold…” — The New York Times
  • “Bring the item outside and brush off the excess mold to prevent the mold spores from getting inside your home.” — Good Housekeeping 
  • “… a Utah-based company, claimed it’s mold remediation products could provide ‘90+ day protection’ against COVID-19.” — KIRO 7
  • “… sheep eat the vines’ young leaves, clearing the way for more sunlight and air to reach the grapes, which helps prevent mold and mildew while promoting even ripening and deep flavor.” — Food & Wine 

If something is in the process of decaying and developing fungal growth, it is “moldy” (adjective) or “molding” (present participle of the intransitive verb mold). 

Sentence examples: 

  • “If your bread is moldy, it is safest to throw out the whole loaf since mold’s roots can spread undetected to the naked eye.” — Insider
  • “The interiors of large round hay bales also naturally ferment, which keeps them from molding and rotting.” — Forbes
  • “The most recent annual inspection by the [MHD] in June 2019 lambasts the conditions finding containers of dried, spoiled and molded food…” — Essence

Synonyms

(n.): Fungus, growth, mildew, must, mouldiness, mustiness, spoilage.

(v.): Break down, corrupt, curdle, decay, decompose, fester, molder, putrefy, rot, sour, spoil.

Antonyms

(v.): Keep, ripen. 

Mold = soil

Last but not least, English uses the noun mold or mould to reference loose garden soil from organic matter (i.e., leaf mold or leaf mold in the United Kingdom).

Sentence examples:

  • “Don’t freak out over the word mold. Leaf mold is nothing more than composted leaves, and it has no nasty odors – just a rich earthy smell, like the forest floor.” — The Detroit Daily News 
  • “We can still obsess over each plucky seedling; gather leaves for leaf mould; dream of sea buckthorn hedging.” — The Guardian 

Synonyms

(n.): Clod, dirt, earth, ground, humus, loam, soil. 

What does break the mold mean?

If someone “breaks the mold” or “mould,” it means they’ve ended a rigid pattern and replaced it with something radically different.

Sentence examples: 

  • The Bush women were not destined to break the mold — only to maintain it and shape it ever so gently with their own style, personality and predilections.” — The Washington Post
  • “So effortlessly does Darkoo break the mould, that she didn’t foresee the flood of speculation about her gender and sexuality.” — British Vogue

Where do the words mold and mould come from?

According to Glynnis Chantrell in The Oxford Dictionary of Word Histories, the earliest use of English mold involves the sense of soil or leaf mold. Initially spelled molde, the Old English noun stems from a Proto-Germanic base to mean ‘pulverize or grind,’ and shares connections to Old High German molta (‘soil’) and the Latin verb molere (‘to grind’) (334). 

The Old English use of molde to describe “the earth of the grave” is a result of Christian influence, but that’s not the only way religion fashioned the noun. As noted by Merriam-Webster’s Dictionary, archaic uses of mold reference “earth that is the substance of the human body.” 

Merriam-Webster lists a historical example from William Shakespeare’s play Henry V (c. 1599): “Be merciful, great Duke, to men of mould.” Shakespeare’s unique use of mould derives from 14th century English in reference to the Christian Bible, where several Earthly substances are connected to the creation of the human body (a more knowledgeable explanation can be read here). 

The use of mold for forms and decay appeared in Middle English, where ‘to mould’ (to form) derived from Old French modle via Latin modulus (measure). ‘To mould,’ as in ‘to decay,‘ is likely a derivative of Scandinavian moul or Old Norse mygla, both meaning ‘to grow mouldy’ (334). 

According to the Online Etymology Dictionary, our secondary sense of mold initially referenced a person’s “fashion,” “nature,” and “character,” where Latin modulus taps the meaning of ‘measure’ and ‘model’ to describe one’s ‘manner.’ By the 14th century, English speakers used the noun and verb to describe cast ironing, where the term was later adopted for kitchen tools in the 16th century. 

When to use mold vs. mould?

Whenever there’s a difference between “American English” and “British English,” writers are quick to ask whether a spelling only applies to England or if the British variant also applies to Australian, South African, and Canadian English. 

The term “British English” assumes English typical of all the British Empire’s current and former territories (now known as the Commonwealth of Nations or British Commonwealth). 

Australia, Australia, New Zealand, Canada, and South Africa are five of 54 sovereign states of the British Commonwealth. Therefore, any native English speaker from these former colonies is more likely to use British spellings over American ones. 

Since Canada and the United States are neighbors, there are gray areas between American and Canadian English. But when it comes to mold versus mould, “mould” is the Canadian Oxford Dictionary‘s primary spelling. 

In summary, it’s fair to assume that “mold” is always the correct English spelling if you’re writing for an American audience. For audiences outside of the United States, they are more likely to recognize “mould” as the most correct form. 

Additional reading

If you’re interested in learning more about British vs. American English, The Word Counter has you covered. Check out our lessons on topics like:

Test Yourself!

Test how well you understand the difference between mold and mould with the following multiple-choice questions. 

  1. True or false?: Mold and mould have different spellings because they are different words.
    a. True
    b. False
  2. Which of the following is not a British spelling variant?
    a. Leaf mould
    b. Mould
    c. Leaf mold
    d. A and C
  3. Which is not an American spelling variant?
    a. Mould
    b. Leafmold
    c. Mouldy 
    d. All of the above
  4. Old English molde references _____________. 
    a. Cast ironing
    b. Soil and leaf mold
    c. Mold growth
    d. The Bible
  5. The use of mold to describe fungi is thought to have a ____________.
    a. Old French and Latin origin 
    b. Old English origin 
    c. Scandinavian origin
    d. All of the above

Answers

  1. B
  2. C
  3. D
  4. B
  5. C

Grammar sources

  1. Allen, G. “From Dust to Dust.” Answers in Genesis, 15 Feb 2012. 
  2. Chantrell, Glynnis, Ed. “Mould: 1–3.” The Oxford Dictionary of Word Histories, Oxford University Press, 2002, p. 334.
  3. Harper, D. “Mold.” Online Etymology Dictionary, Etymonline.com, 2021. 
  4. Leaf mold.” Lexico, Oxford University Press, 2021.
  5. Mold.” Lexico, Oxford University Press, 2021.
  6. Molding.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., 2021.
  7. Mould.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., 2021.

Sentence examples cited

  1. Barton, S. “The Perth Mint Has Recast This Gold Bar More Than 65,000 Times.” Bloomberg, 15 Feb 2019. 
  2. Edwards, B. “Over 100 Inmates At Parchman Sue Mississippi Officials Over ‘Barbaric’ Conditions.” Essence, 26 Feb 2020.
  3. Eisner, J. “For three generations of Bush women, personal pain and a public spotlight.” The Washington Post, 19 Mar 2021.
  4. Hass, N. “The Making of an Especially Intricate Fendi Baguette Bag.” The New York Times Style Magazine, 19 Mar 2021.
  5. Jones, P. “Investment Casting: What You Need To Know.” The Science Times, 19 Mar 2021.
  6. Kim, J. “How to Get Rid of Mold in Every Corner of Your House.” Good Housekeeping, 8 Jan 2021.
  7. KIRO 7 News Staff. “Mold removal company charged after falsely claiming products could protect against COVID-19.” — KIRO 7, 22 Feb 2021. 
  8. Kuta, S. “Meet the Wooly Weeders, the Adorable Heroes of California Wine.” Food & Wine, 23 Mar 2021. 
  9. Lee, J. “Instagram is the new mixtape for high school hoops.” ESPN, 19 Aug 2020. 
  10. Lu, S. “Why you should never eat moldy bread.” Insider, 12 Jun 2020.
  11. Lundquist, C. “BYU Football Offers Nathan Kent.” Sports Illustrated, 24 Mar 2021.
  12. Mendelssohn, C. “‘I was so in love with my first garden that I wrote a book about it.’” The Guardian, 20 Mar 2021.
  13. Michalski, D. “Personal Business; Mold Can Be an Insurance Mess for Homeowners.” The New York Times, 16 Jun 2002. 
  14. Mukhtar, A. “Rising Afroswing Star Darkoo Is Here To Change The Music Industry – And The World.” British Vogue, 29 Dec 2020. 
  15. Recipe: Bavarian Cream a la Doris from ‘Joe Beef: Surviving the Apocalypse.’’ Houston Chronicle, 3 Dec 2018. 
  16. Smith, K. N. “This Is Why Hay Bales Are Round.” Forbes, 18 Mar 2021. 
  17. Szerlag, N. “Gardening: Don’t toss leaves – they are free fertilizer.” The Detroit News, 13 Oct 2016.
  18. Tedeschi, B. “Installing Molding and Tin Ceilings.” The New York Times, 11 Feb 2015.